.a{
    /*导航栏样式*/
    background-image: url("images/2.png");
    background-repeat: no-repeat;
    background-size: 100% 100%;
    height: 100px;
    width: 100%;
    position: fixed;
    top: 0;
    z-index: 999;
    box-shadow: 0 1px 5px rgba(0,0,0,.15);
    border-bottom: 1px solid #e5e5e5;
    font-size: 14px;
    color: #333;
    line-height: 50px;
    padding: 0 10px;
    box-sizing: border-box;
}
.active{
    color: #fff;
    background-color: #fff;
    border-radius: 5px;
    border: 1px solid #fff;
    box-shadow: 0 1px 5px rgba(0,0,0,.15);
    margin-left: 70px;
    margin-right: 10px;
    margin-top: 10px;
    margin-bottom: 10px;
    padding: 5px 10px;
    font-size: 14px;
    color: #333;
    line-height: 100px;
    box-sizing: border-box;
    text-decoration: none;
    cursor: pointer;
    transition: all .3s;
}
.image{
    width: 400px;
    height: 400px;
    border-radius: 5px;
    box-shadow: 0 1px 5px rgba(0,0,0,.15);
    margin-top: 100px;
    margin-left: 60px;
}
.b{
    color: #fff;
    background-color: #fff;
    border-radius: 5px;
    border: 1px solid #fff;
    box-shadow: 0 1px 5px rgba(0,0,0,.15);
    margin-left: 680px;
    margin-right: 10px;
    margin-top: 10px;
    margin-bottom: 10px;
    padding: 5px 10px;
    font-size: 14px;
    color: #333;
    line-height: 100px;
    box-sizing: border-box;
    text-decoration: none;
    cursor: pointer;
    transition: all .3s;
}